USB: cxacru: ignore error trying to start ADSL in atm_start

The sysfs adsl_status attribute ignores (aside from returning -EIO to the
user) any error sending a START/STOP command to the device and there is at
least one firmware which never sends a response but appears to work
regardless.  Therefore atm_start should also continue if an error is received
so that such firmware is usable.

The official Conexant driver doesn't expect a reply either but this is for
another device (E2 router) and a commonly used firmware does respond.

Also, there is no point in changing -ECONNRESET to -ETIMEDOUT since nothing
ever checks for either of these values.

Signed-off-by: Simon Arlott <simon@fire.lp0.eu>
Cc: Duncan Sands <duncan.sands@math.u-psud.fr>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>